Holding device



Aus 22. 195o w. BYRD, JR 2,519,435

HOLDING DEVICE Filed Aug. 21, 194e 2 sheets-sheet 1 INVENTOR. WILLIAM BYRD JR.

ATTORNEH' Aug. 22, 1950 w` BYRD, JR 2,519,435

HOLDING DEVICE Filed Aug. 2l, 1.946` 2 Sheets-Sheet 2 f"- /HII'IIII' 47 I' lz/g.4.

| Ult |lill INVENTOR.

WILLIAM BYRD JR.

BYMMIM. y-C/MM ATTORNEW'.

Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE HOLDING DEVICE William Byrd, Jr., Princeton, N. J. Application August 21, 1946, Serial No. 692,087 5 Claims. (Ci. 292-40) The present invention relates to an improved magnetic catch for holding hinged or sliding members.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefro'm, or may be learned by praetice with the invention, the same being realized and attained by means of the instrumentallties and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate several embodiments of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a view in vertical medial section oi' one form of door stop intended to hold a door in the full open position Figure 2 is a fragmentary side elevation taken alng the lines 2 2 of Figure 1;

Figure 3 is a view partially in elevation and partially in section oi another form oi door stop embodying my invention;

Figure 4 is a, view in elevation, with portions broken away for clarity of another embodiment of my invention;

Figure 5 is a view, partially in section, of the magnet assembly of Figure 4: and

Figure 6 is a view in elevation of a variation of the elements oi Figure 4.

An object of my invention is to provide a magnetic door stop capable of holding a door in the fully open or closed position against forces of the magnitude produced by air currents or spring or weight devices which may be provided for closing purposes. Another object of my invention is to provide a magnetically operated friction brake ting position.

Referring now in detail to the accompanying drawings, in Figure 1, a magnet assembly i. is fastened to a door 2. in auch a position that when the door is fully opened, the working face of the magnet engages a keeper mon form of l. carried by a comtonlike ends B. 1. respectively. which engage a coupling 8, ol' rubber or other flexible and shock absorbing material.

The magnet l, is composed ot a cylindrical cup 9. of masnetizable material in which is alloy.

One pole face of the the bottom of age gap I1. The pole areas l5 and I3. and the and length of the permanent upon repeated contact and non-contact of magnetic circuit and an inexpensive and compact magnet to develop a tractlve force which is adequate for the intended application.

Referring to Figure 3, magnet 2D, is similar to, but may be somewhat larger than the magnet o Figures l, 2. The magnet 20, is mounted on door 2 I by use of a strap 22. and screws 23. The working face 2l, of the magnet parallels the iioor 25, and is slightly below the bottom surface 2B, of the door. A plate 21, of magnetizabie material is hingedly attached at pivot 2B, to a plate 29, which is recessed in the door and fixed thereto by screws 30. Plate 21, has a slightly curved portion 3i, and a recessed portion 32, and is so positioned that when the door is swung toward a limiting position, either fully open or fully closed, the door and magnet face will pass immediately above it.

As the magnet force causes the plate to floor until it contacts the magnet face. Further motion of the door is opposed by the frictional retarding effect caused by the adherence of the plate to the magnet. A braking action is thus provided.

The recessed portion 32, of the plate 21, is so placed that it engages the magnet face 24 when the door is in its limiting right hand position. The force required to move the door to the left from this position is multiplied by the stopping effect of shoulder 33. Through adjustment of the angle of this shoulder and of the bevel of the edge of the magnet lace, the force required to break the magnetic hold can be controlled.

Referring now to Figure 4, a holder 35, is fastened to the floor 36, by screws 31. Within the holder is a magnet assembly 39, resting on a cushion 4l) of sponge rubber or other suitable material` The magnet assembly 39 is provided with considerable freedom of vertical motion, but cannot be pulled out the top of the holder 35 because its enlarged portion 4l, will strike the constriction I3, of the holder. This construction is provided to minimize the likelihood of theft of the magnet assembly.

The top face M, of the magnet assembly is provided with two concentric polepieces as will be described in connection with Figure 5. The holder 35, is installed in the usual position of door stops. A bracket 46, of high magnetic permeability material is mounted on the door 41, by screws 4B. The bracket is so positioned that as the door swings (toward the right) to its full open position, the bracket passes directly over the face M, of the magnet assembly.

It will be appreciated that the vertical positioning of the face Il with respect to the bottom surface 49. of the bracket 46 is not at all critical. if face M is slightly higher than surface 49, the magnet assembly 39 is pushed downward and the cushion l slightly compressed. If on the other hand, face Il is slightly below surface 49, attraction will cause the magnet assembly 39 to rise until face M attaches itself to surface 49. As soon as the magnet assembly and bracket become attached, the holder acts to prevent further motion of the door. However, further motion is still possible if sufficient force is applied to overcome the frictional resistance of sliding the bracket across the magnet face. It will be understood that as the door swings rapidly to- .vard its full open position, the magnet assembly and keeper provide automatic braking operation, `wringing the door to rest over a short distance and then holding passes over plate 21, attractive hinge upward off the exerted manually on the door to break the magnetic hold. I have found that magnet assemblies which resist the sliding of a keeper across their face with a force of the order of 5 to l5 pounds are generally very satisfactory. The construction of a suitable type of magnet assembly is shown in Figure 5 which is a half-section view of a cylindrical magnet.

Referring to Figure 5, a casing 50 of high permeability material has a cylindrical interior in which is fitted a sleeve 5l oi non-magnetic material. A cylindrical permanent magnet 52, axially magnetized abuts the inside bottom surface of the casing 50 and is centrally positioned by the sleeve 5I. A polepiece 53 abuts the top of the permanent magnet 52. The top portions of the casing, sleeve and polepiece provide a fiat surface which contains annular poles 5I, 55 separated by the gap 56. The bevel 51 and the recess 5B serve to limit the polar areas 54, 55. Concentration of the flux passing between the magnet face and an attached permeable body is thus obtained and gives the magnet assembly its high performance.

Figure 6 shows a variation of the devices of Figures 4. 5 employed to operate in the closed position of doors. In Figure 6 the magnet holder B0, is mounted on the door 6i and the bracket 62, is mounted on the frame 63, above the top of the door. The magnet assembly 64, rests on a cushion not shown) in the holder.

It is evident that the magnet assembly can be carried by the door or attached to the wall or floor and that the bracket can be correspondingly positioned. It is possible to insert a magnetic plate in the bottom of the door to avoid use of an exposed bracket or other device serving the same purpose. When such a plate is used it is desirable to make a recess in the floor to receive the magnet assembly and holder.

The cylindrical magnet construction which I have described provides the required holding power in a compact assembly. It should be un derstood, however, that other designs and shapes of permanent holding magnets such as the rectangular types disclosed in my copending application Serial No. 692,686 entitled Magnetic Circuit Holding Device, led August 2l, 1946, now abandoned, may be substituted for the magnet assembly described herein. When the magnet is of rectangular shape, it will be understood that it can be retained by a box type holder or a rectangular clamping bracket.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the inention and without sacrificing its chief advanage.

What is claimed is:

l. A magnetically loaded friction device for braking the motion of a hinged door in the region of one of its limiting positions, comprising a permanent magnet member having a polar surface and a magnetically permeable member, the polar surface of said magnet and an opposable surface of said permeable member being adapted to have frictional engagement with each other, one of said members being mounted on said door and the other member being mounted on a surface near one of the limiting positions of said door, one o! said members being vertically slidable toward the other, said members being so positioned that the it open until sumclent torce is 'Il opposable surface of said permeable member and the polar surface of said magnet member will be brought into adjoining relationship as the door approaches said limiting position, and will be mutually attracted into slidable frictional contact, as the door nears the limiting position at which said surface-mounted member is located. due to the magnetic attraction between said members.

2. The device of claim 1 in which said permanent magnet member comprises a magnetic circuit comprising a permanent magnet at least partially surrounded by a casing of highly permeable material, said casing being slightly spaced from said permanent magnet adjacent one pole of the permanent magnet to provide a leakage gap and a non-magnetic solid material in said gap and spacing said magnet from the surrounding highly permeable material.

3. The device of claim 1 in which one of said members is mounted on a surface near the limiting open position of said door.

4. The device oi claim i including means for resiliently supporting said magnet member, in a position where the polar surface of said magnet member will engage the opposable surface of said permeable member to permit depression of said magnet member against resistance of said means.

5. The device of claim l, wherein the vertically slidable member is provided with a resilient mounting urging it toward the other member, and where the contacting surfaces of the two members are disposed in overlapping horizontal planes, whereby the frictional force between the two members is due both to said resilient mounting and to the mutual magnetic attraction.

WILLIAM BYRD. Jn.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

